THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[SECOND SERIES.] 



" per litora spargite museum. 



Naiades, et circilm vitreos considite fontes : 

 PoUice virgineo teneros hic carpite flores : 

 Floribus et pictum, divse, replete canistrum. 

 At vos, o Nymphse Craterides, ite sub undas ; 

 Ite, recurvato variata corallia trunco 

 Vellite muscosis e rupibus, et mihi conchas 

 Ferte, Deas pelagi, et pingui conchylia succo." 



N. Parthenii Giannettatii Eel. 1. 



No. 25. JANUARY 1850. 



I. — Observations on the Corijugation 0/ Closterium Ehrenbergii. 

 By the Rev. W. Smith, F.L.S. 



[With a Plate.] 



1 HE conjugation of Closterium Ehrenbergii (Menegh.), under 

 the name of Closterium lunula, has been described in a paper by 

 M. Morren, ^ Annales des Sciences Naturelles/ 2nd ser. torn. v. 

 1836, but the phsenoraenon does not appear to have met the eye 

 of any late observer in this country, and is wholly unnoticed by 

 the acute and careful authors of the ^ British Desmidiese.' 



I have had an opportunity, during two successive seasons, of 

 noticing the circumstance in question, and the facts elicited seem 

 to vary in some important respects so materially from those re- 

 corded by M. Morren, and are in themselves so different from the 

 ordinary ph£enomena which accompany the conjugation of other 

 Closteria, or indeed of any other of the Besmidiece, that I have 

 thought it might be interesting to those engaged in such inves- 

 tigations to state the particulars which have fallen under my 

 notice. 



On the 23rd March 1848, 1 first discovered Closterium Ehren- 

 bergii in a state of reproduction. On this occasion the period of 

 conjugation had evidently nearly expired, as but few individuals 

 were in that condition, and the mucus stratum, which results 

 from the aggregation of conjugating fronds, had almost wholly 



Ann. ^ Mag. N. Hist. Ser. 2. Vol. v. 1 



